Fluorinated polymers with pendant side chains containing groups such as sulfonamide and sulfonic acid are known in the prior art and possess utility as ion-exchange resins. The resins are useful in the form of films wherein it is necessary to have thermal and chemical stability such as for use as a membrane in an environment of a electrolytic chlor-alkali cell. An example of such utility is disclosed in U.S. Pat. No. 2,251,660, published Apr. 26, 1973.
A serious limitation of use of such ion-exchange resins in the form of films is that physical strength of the film is unduly low for specific applications. Additionally, a tear or perforation in a film may quickly progress in length as is characteristic of many films. Therefore, an initial perforation in the film renders the film quickly unfit and undesirable for its intended usage. Use of a greater film thickness for increased physical strength denotes greater expense as well as in many instances reduced conductivity for ion-exchange purposes.